1. Field of the Invention
This invention relates to multi-dial electric meter registers and more particularly to a combined dual rate electric energy and on-off maximum power demand register.
2. Description of the Prior Art
The mechanical dial registers of electric utility billing meters typically perform two general measuring functions, one being to totalize the rotations of a watthour meter movement and indicate, at dial pointers, the corresponding watthours of energy consumption. The other general measuring function is to only totalize the maximum number of rotations occurring during any one of successively occurring short-time intervals and to indicate the corresponding maximum watts of power demand. It is further known to selectively measure watthours or watt demand at so-called time of day or multi-rate registers so that energy consumption and/or power demands are separately indicated for different times of day or when consumption occurs above or below a predetermined rate or demand level. This permits different charges to be made for electric energy usage during on-peak and off-peak load conditions on an electric utility supply and distribution network.
Prior art electric meters are described in U.S. Pat. Nos. 671,272; 1,576,158; and 2,145,069 wherein energy consumption is measured either on a single register at different rates, as in the U.S. Pat. No. 671,272 or on two separate registers as in the latter two patents and the meters also measure power demand at an additional indicator. In each of aforementioned meter mechanisms, solenoid plungers actuate either a metering rate control resistor or a gear shift in a dual energy measuring register. An additional solenoid is associated with demand metering indicators in the U.S. Pat. Nos. 2,145,069 and 671,272.
Examples of time of day watthour registers are disclosed in U.S. Pat. Nos. 1,078,208; 2,000,736; 2,132,256; and 2,139,821. The aforementioned meter registers include two dials having associated gear trains. A watthour meter movement is connected to either of the dial gear trains under control of a clock mechanism to indicate on-peak and off-peak energy consumption. The latter two patents include pivotally mounted arms or plates for coupling a single driving gear to either of the two driven input gears providing separate inputs through the two dial gear trains. The aforementioned patents do not concurrently control a maximum demand register as in the present invention.
Examples of on-peak maximum demand registers are disclosed in U.S. Pat. Nos. 1,586,648 and 3,913,014; the latter being assigned to the assignee of this invention. These patents disclose a cam rotated by the demand gearing timing motor so that the maximum demand register is only engaged with the maximum demand indicators during daily on-peak periods.
Accordingly, it is desirable to have a simple and compact multi-dial meter register capable of providing selective on-peak and off-peak measurements of both electric energy consumption and maximum electric power demand.